Sjögren's syndrome is an autoimmune disorder in which immune cells attack and destroy the glands that produce tears and saliva. The hallmark symptoms of the disorder are dry mouth and dry eyes. Sjögren's syndrome may also cause skin, nose and vaginal dryness, and can affect other organs of the body including the kidneys, blood vessels, lungs, liver, pancreas and brain. Sjögren's syndrome affects 1-4 million people in the United States, with women being nine times more likely to develop the disease. The majority of Sjögren's sufferers are at least 40 years old at the time of diagnosis. Sjögren's syndrome can occur as a primary condition or as a secondary disorder in association with other autoimmune diseases, such as systemic lupus erythematosus (“lupus”) or rheumatoid arthritis.
Sjögren's syndrome can damage vital organs of the body with symptoms that may remain stable, worsen, or go into remission. Some patients experience only the mild symptoms of dry eyes and mouth, while others go through cycles of good health followed by severe disease. While many patients are able to treat problems symptomatically, others suffer from blurred vision, constant eye discomfort, recurrent mouth infections, swollen parotid glands, hoarseness, and difficulty in swallowing and eating. Debilitating fatigue and joint pain can seriously impair quality of life. The diagnosis of Sjögren's syndrome is made based on various combinations of subjective and objective evidence of dryness and the presence of markers of autoimmunity (autoantibodies) and/or inflammation in the salivary gland. More objective diagnostic biomarkers are highly desirable to improve the accuracy of Sjögren's syndrome diagnosis.
There is currently no known cure for Sjögren's syndrome, nor is there a universally effective treatment to restore gland secretion. Treatment is generally symptomatic and supportive, including moisture replacement therapies to relieve the symptoms of eye and mouth dryness. A subset of patients has some response to orally available drugs (pilocarpine and cevimeline) that stimulate saliva production but the response is usually limited and many patients do not tolerate the drugs due to side effects. Non-steroidal anti-inflammatory drugs can be used to treat musculoskeletal symptoms. For individuals with severe complications, corticosteroids or immunosuppressive drugs are often prescribed. These drugs can have serious side effects. Therefore, a need exists to not only accurately diagnose patients with Sjögren's syndrome, but to identify viable therapeutic targets for treatment of the disease.